Self-rupturing diaphragm assembly



June 2, 1964 e. F. MECHLIN, JR., ETAL 3 SELF-RUPTURING DIAPHRAGM ASSEMBLY Filed May 8, 1962 2 Sheets-Sheet l GEORGE F. MECHLIN JR.

BY ROBERT D. RUNG H IO 7 ATTORNEY n 1964 e. F. MECHLIN, JR, ETAL 3,135,163

SELF-RUPTURING DIAPHRAGM ASSEMBLY Filed May 8, 1962 2 Sheets-Sheet 2 m m 9/ lllllll/ INVENTORS GEORGE F. MECHLIN JR. BY ROBERT D. RUNG RNEY United States Patent 3,135,163 SELF-RUPTURING DIAPHRAGM ASSEMBLY George F. Mechiin, In, and Robert D. Rung, Saratoga,

Califi, assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed May 8, 1962, Ser. No. 193,345 2 Claims. (Cl. 89-5) This invention relates to sealing means, and more particularly a self-rupturable diaphragm for sealing an enclosure or the like.

When a Polaris missile is to be launched from its submerged launching tube on a fleet ballistic type submarine or other type of carrier, the missile should be kept dry in the tube until the instance of launching. Since the process of opening the launcher muzzle hatch requires several seconds, a temporary sealing diaphragm is provided over the muzzle end to isolate the missile from the sea water and to permit instant firing. This requirement presents a diflicult problem because the diaphragm must be sufliciently strong to withstand high differential pressures and be ruptured within one-tenth of a second after actual missile first motion. Furthermore, the diaphragm must be ruptured in a predetermined pattern to avoid damage or interference to the missile from pressure loads or diaphragm debris and to avoid pressure increases beyond those acceptable to the missile.

The instant invention provides a diaphragm which is sufliciently strong to withstand the differential pressures to which it is likely to be subjected to, and, yet, which can be ruptured instantly in a predetermined pattern that will prevent interference with the launched missile. This has been accomplished in one embodiment of the invention by utilizing a diaphragm made of polyester plastic and attaching thereto one or more explosive cords arranged along a predetermined pattern so that the diaphragm will be ruptured or fractured in several pieces. The explosive cord is ignited by a plurality of initiators or detonators disposed in spaced relation along the explosive cord to ensure complete ignition of the cord and separation of the diaphragm from the supporting launching tube.

An important object of the invention is to provide a diaphragm that can be instantaneously destructed and effectively cleared of the sealed area.

Another object to provide such a diaphragm that can be reliably severed and uniformly removed.

A further object is to provide such a diaphragm for use in a missile launching tube capable to withstand high differential pressures and which can be instantly ruptured and uniformly disposed to prevent interference with the passage of the missile.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a top plan View of the muzzle-end of a Polaris-type launching tube with the hatch removed, being sealed by the self-rupturing diaphragm of this invention;

FIGS. 2 and 3 are cross-sectional views of the diaphragm and explosive cord attached thereto taken along lines II-II and III-III respectively, of FIG. 1;

FIG. 4 is a vertical section taken through an initiator assembly on the muzzle end of the missile launching tube along line 1V-IV of FIG. 1;

FIG. 5 is an enlarged partial vertical section taken through the initiator along line V-V of FIG. 1; and

FIG. 6 is top plan diagrammatic view of a modified arrangement of the explosive cord on a non-flexing diaphragm.

Referring to the figures where like reference numerals refer to similar parts throughout the drawing, there is shown the muzzle end of a tube assembly 10, for launching Polaris-type missiles, not shown. The muzzle end of the launching tube is sealed by a diaphragm 12 supported around the periphery between upper and lower clamping rings 14 and 16, respectively, secured together by a plurality of bolts 18 which extend through openings in the diaphragm. The clamping rings are supported on a seal assembly 20 for the launching tube which forms no part of this invention.

Diaphragm 12 may be made of flexible material, such as is used in the modification of FIGS. 1 to 5 inclusive or, non-flexible material as covered by the modification in FIG. 6. In the modification of FIGS. 15 the diaphragm material is a tough membrane, such as polyester plastic sheet commonly known as Mylar. Using this material, a diaphragm thickness in the order of .070 inch has been found to be satisfactory which should be capable of withstanding at least 30 psi. differential pressure when the launcher tube is pressurized with a fluid to approximately equalize the pressure of the sea Water acting on the outer side of the diaphragm.

To insure rupture of the tough diaphragm membrane in a predetermined pattern within the time restrictions, i.e. in the order of one-tenth of a second, an explosive cord 22 is affixed to diaphragm in along a predetermined pattern. For a flexible diaphragm member the explosive cord is arranged as a single length, skirting the periphery of the clamping rings and having one end directed radially inwardly terminating short of the peripheral portion. This pattern will enable the explosive cord to cut the diaphragm symmetrically to minimize disturbances to the missile trajectory. The explosive cord is variously known as LEDC (low energy detonating cord) and MDF (mild detonating fuse). As shown in FIGS. 2 and 3 the cord is preferably shaped as an inverted V and aflixed to the upper side of diaphragm 12 by a Waterproof tape 24. A tunnel 26 may be positioned between the tape and the explosive cord along the radial segment to permit the explosive cord to slip radially along the diaphragm to survive flexing of the diaphragm.

The size of explosive cord 22 is selected in the range wherein cutting is reliable but not to the extent that the blast will damage the missile.

The explosive cord is ignited by one or more ignitor assemblies 28 spaced along the cord, four being illustrated. As detailed in FIGS. 4 and 5, each ignitor assembly 28 comprises an electrical connector post 30 supported in the clamping rings and electrically connected to a detonator 32 supported in a base 34 to the outer surface of the diaphragm by a shield 36 in form of a tape. Detonator 32 has a notched end 38 to straddle and ignite the explosive cord when energized.

FIG. 6 shows a diagrammatic sketch of a modified pattern of explosive cord applied to a non-flexible type of diaphragm 40. In this modification the explosive cord is arranged in two lengths 42 and 44 arranged in an S-shaped pattern so as to divide the surface of the diaphragm in quadrants. Each explosive cord length is provided with initiators 46 at both ends.

The present invention provides temporary sealing means for a missile launching tube that is tough and reliable, and which can be instantaneously ruptured in a predetermined pattern to minimize disturbances to the missile trajectory. Separation of the diaphragm is accomplished by means of an explosive cord, which may be shaped or unshaped, and applied to either the exposed and/or inner face of the diaphragm in a variety of patterns. The diaphragm can be constructed of flexible or stiff material with a pattern selected for the explosive cord that will ensure the desired fragmentation.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. A self-rupturable diaphragm assembly for sealing a circular underwater opening in a missile launching tube comprising:

(a) a tough and flexible flat diaphragm member covering said opening; v

(b) means for clamping said diaphragm member to the tube;

(0) an explosive cord attached to said diaphragm in a predetermined pattern, a portion of said cord arranged entirely around the periphery of the tube, and a portion of thecord extending across a face of said diaphragm; and

(d) means for attaching said explosive cord to the diaphragm to permit relative movement therebetween;

(e) means for igniting said explosive cord at spaced intervals along said cord whereby the diaphragm is severed along said pattern to minimize interference with the missile passing through the tube.

2. A self-rupturable diaphragm assembly for sealing a circular underwater opening in a missile launching tube comprising:

4* (a) a tough and flexible diaphragm member of a single layer thickness covering said'openingy (b) means for clamping said diaphragm member to the tube;

(0) an explosive cord attached to said diaphragm in a predetermined pattern, a portion of said cord arranged entirely around the periphery of the tube and a portion of the cord extending across a face of said diaphragm; and

(d) said explosive cord being attached to the diaphragm by an adhesive tape for water proofing the connec- References Cited in the file of this patent UNITED STATES PATENTS.

2,349,009 Schwab May 16, 1944 2,511,005 Pool June 13, 1950 2,809,583 Ortynsky et a1. Oct. 15, 1957 7 2,996,985 Kratzer Aug.22, 1961 3,072,022 Wood et al. Jan. 8, 1963 FOREIGN PATENTS Canada Feb. '7, 

1. A SELF-RUPTURABLE DIAPHRAGM ASSEMBLY FOR SEALING A CIRCULAR UNDERWATER OPENING IN A MISSILE LAUNCHING TUBE COMPRISING: (A) A TOUGH AND FLEXIBLE FLAT DIAPHRAGM MEMBER COVERING SAID OPENING; (B) MEANS FOR CLAMPING SAID DIAPHRAGM MEMBER TO THE TUBE; (C) AN EXPLOSIVE CORD ATTACHED TO SAID DIAPHRAGM IN A PREDETERMINED PATTERN, A PORTIN OF SAID CORD ARRANGED ENTIRELY AROUND THE PERIPHERY OF THE TUBE, AND A PORTIN OF THE CORD EXTENDING ACROSS A FACE OF SAID DIAPHRAGM; AND (D) MEANS FOR ATTACHING SAID EXPLOSIVE CORD TO THE DIAPHRAGM TO PERMIT RELATIVE MOVEMENT THEREBETWEEN; (E) MEANS FOR IGNITING SAID EXPLOSIVE CORD AT SPACED INTERVALS ALONG SAID CORD WHEREBY THE DIAPHRAGM IS 